Reproductive performance following unilateral ovariectomy for treatment of ovarian tumors in 7 mares

Abstract

Unilateral ovariectomies were performed on 7 mares under inhalation anesthesia for treatment of ovarian tumors. All mares were evaluated for a 2-year history of infertility; 6 mares showed persistent anestrus while 1 mare showed persistent estrus. The presumptive clinical diagnosis of the tumors was made by rectal palpation and ultrasonographic imaging of the ovaries. The affected ovaries were large, spherical, and hard, and the contralateral ovaries were small and inactive. The flank approach technique was used for all of the mares. All mares were operated on successfully. One of the mares had delayed healing and abscess formation in the incision line. In one postovariectomy mare, the contralateral ovary remained small and inactive; the histopathological diagnosis for the ovarian tumor was fibrothecoma and the mare remained infertile after the ovariectomy. The other 6 mares returned to estrus (average: 154 +/- 30 days), were capable of breeding, and exhibited normal behavior after the surgery. These mares were diagnosed histopathologically with ovarian granulosa theca cell tumors (GTCT). These mares were not bred until the next breeding season. After breeding (average time to successful conception: 296 +/- 20 days after surgery), these mares became pregnant and gave birth to normal foals uneventfully.